This application is revised from the approved application (1 ROI EYO 3796-01). The critique in the summary statement of the original application (received 5/15/81) was the basis for this revision. Visual motion thresholds will be studied in the program which can be divided into 3 component parts: (1) Psychophysical measurements of motion displacement thresholds in man, (2) electrophysiological measurements of motion displacement thresholds of single retinal and cortical units in cat and monkey, and (3) determination of optimum stimulus conditions for moving stimuli in clinical kinetic perimetry. The International Perimetric Society has noted the need for research on visual motion in kinetic perimetry, and has identified our work as pertinent to the problem. The long term objectives are to define motion displacement thresholds in man, determine the physiological basis for displacement thresholds and apply these findings to visual field testing. Motion paradigms have been developed for use in both psychophysical and electrophysiological experiments (1-6). Specific hypothesis based upon monkey retinal receptive field properties was proposed to account for the exquisite sensitivity of primates, including man, to motion. From these scientific studies, some optimum stimulus parameters for the detection of motion have been found (7). This program could fund an established program and is consistent with the NIH national plan for 1978-82 in vision research because (1) the neurophysiology of primate retina is examined. (2) the psychophysical and physiological determinants of motion sensitivity in retinal and higher visual neurons are studied, and (3) psychophysical techniques are applied to improve clinical diagnosis of visual field disorders.